Heat shock protein (HSP) 90 is expressed in most living organisms, and several client proteins of HSP90 are necessary for cancer cell survival and growth. Previously, we found that HSP90 was cleaved by histone deacetylase (HDAC) inhibitors and proteasome inhibitors, and the cleavage of HSP90 contributes to their cytotoxicity in K562 leukemia cells. In this study, we first established mouse xenograft models with K562 cells expressing the wild-type or cleavage-resistant mutant HSP90β and found that the suppression of tumor growth by the HDAC inhibitor suberoylanilide hydroxamic acid (SAHA) was interrupted by the mutation inhibiting the HSP90 cleavage in vivo. Next, we investigated the possible function of thioredoxin interacting protein (TXNIP) in the HSP90 cleavage induced by SAHA. TXNIP is a negative regulator for thioredoxin, an antioxidant protein. SAHA transcriptionally induced the expression of TXNIP in K562 cells. HSP90 cleavage was induced by SAHA also in the thymocytes of normal mice and suppressed by an anti-oxidant and pan-caspase inhibitor. When the thymocytes from the TXNIP knockout mice and their wild-type littermate control mice were treated with SAHA, the HSP90 cleavage was detected in the thymocytes of the littermate controls but suppressed in those of the TXNIP knockout mice suggesting the requirement of TXNIP for HSP90 cleavage. We additionally found that HSP90 cleavage was induced by actinomycin D, β-mercaptoethanol, and p38 MAPK inhibitor PD169316 suggesting its prevalence. Taken together, we suggest that HSP90 cleavage occurs also in vivo and contributes to the anti-cancer activity of various drugs in a TXNIP-dependent manner.

Paxlovid is the first approved oral treatment for coronavirus disease 2019 and includes nirmatrelvir, a protease inhibitor targeting the main protease (Mpro ) of SARS-CoV-2, as one of the key components. While some specific mutations emerged in Mpro were revealed to significantly reduce viral susceptibility to nirmatrelvir in vitro, there is no report regarding resistance to nirmatrelvir in patients and animal models for SARS-CoV-2 infection yet. We recently developed xenograft tumors derived from Calu-3 cells in immunodeficient mice and demonstrated extended replication of SARS-CoV-2 in the tumors. In this study, we investigated the effect of nirmatrelvir administration on SARS-CoV-2 replication. Treatment with nirmatrelvir after virus infection significantly reduced the replication of the parental SARS-CoV-2 and SARS-CoV-2 Omicron at 5 days post-infection (dpi). However, the virus titers were completely recovered at the time points of 15 and 30 dpi. The virus genomes in the tumors at 30 dpi were analyzed to investigate whether nirmatrelvir-resistant mutant viruses had emerged during the extended replication of SARS-CoV-2. Various mutations in several genes including ORF1ab, ORF3a, ORF7a, ORF7b, ORF8, and N occurred in the SARS-CoV-2 genome; however, no mutations were induced in the Mpro sequence by a single round of nirmatrelvir treatment, and none were observed even after two rounds of treatment. The parental SARS-CoV-2 and its sublineage isolates showed similar IC50 values of nirmatrelvir in Vero E6 cells. Therefore, it is probable that inducing viral resistance to nirmatrelvir in vivo is challenging differently from in vitro passage.

The drug repurposing strategy has been applied to the development of emergency COVID-19 therapeutic medicines. Current drug repurposing approaches have been directed against RNA polymerases and viral proteases. Recently, we found that the inhibition of the interaction between the SARS-CoV-2 structural nucleocapsid (N) and spike (S) proteins decreased viral replication. In this study, drug repurposing candidates were screened by in silico molecular docking simulation with the SARS-CoV-2 structural N protein. In the ChEMBL database, 1994 FDA-approved drugs were selected for the in silico virtual screening against the N terminal domain (NTD) of the SARS-CoV-2 N protein. The tyrosine 109 residue in the NTD of the N protein was used as the center of the ligand binding grid for the docking simulation. In plaque forming assays performed with SARS-CoV-2 infected Vero E6 cells, atovaquone, abiraterone acetate, and digoxin exhibited a tendency to reduce the size of the viral plagues without affecting the plaque numbers. Abiraterone acetate significantly decreased the accumulation of viral particles in the cell culture supernatants in a concentration-dependent manner. In addition, abiraterone acetate significantly decreased the production of N protein and S protein in the SARS-CoV-2-infected Vero E6 cells. In conclusion, abiraterone acetate has therapeutic potential to inhibit the viral replication of SARS-CoV-2.

Severe acute respiratory syndrome CoV-2 (SARS-CoV-2) is responsible for the current coronavirus disease 2019 (COVID-19) pandemic. Signaling pathways that are essential for virus production have potential as therapeutic targets against COVID-19. In this study, we investigated cellular responses in two cell lines, Vero and Calu-3, upon SARS-CoV-2 infection and evaluated the effects of pathway-specific inhibitors on virus production. SARS-CoV-2 infection induced dephosphorylation of STAT1 and STAT3, high virus production, and apoptosis in Vero cells. However, in Calu-3 cells, SARS-CoV-2 infection induced long-lasting phosphorylation of STAT1 and STAT3, low virus production, and no prominent apoptosis. Inhibitors that target STAT3 phosphorylation and dimerization reduced SARS-CoV-2 production in Calu-3 cells, but not in Vero cells. These results suggest a necessity to evaluate cellular consequences upon SARS-CoV-2 infection using various model cell lines to find out more appropriate cells recapitulating relevant responses to SARS-CoV-2 infection in vitro.

Severe acute respiratory syndrome CoV-2 (SARS-CoV-2) is responsible for the current coronavirus disease 2019 (COVID-19) pandemic. Signaling pathways that are essential for virus production have potential as therapeutic targets against COVID-19. In this study, we investigated cellular responses in two cell lines, Vero and Calu-3, upon SARS-CoV-2 infection and evaluated the effects of pathway-specific inhibitors on virus production. SARS-CoV-2 infection induced dephosphorylation of STAT1 and STAT3, high virus production, and apoptosis in Vero cells. However, in Calu-3 cells, SARS-CoV-2 infection induced long-lasting phosphorylation of STAT1 and STAT3, low virus production, and no prominent apoptosis. Inhibitors that target STAT3 phosphorylation and dimerization reduced SARS-CoV-2 production in Calu-3 cells, but not in Vero cells. These results suggest a necessity to evaluate cellular consequences upon SARS-CoV-2 infection using various model cell lines to find out more appropriate cells recapitulating relevant responses to SARS-CoV-2 infection in vitro.

Purpose: In Korea, the Broselow tape (BT) is widely used to estimate weight in resuscitation. Validation of BT in Korean children is essential because the tool was developed based on children’s weight and height in the United States. The validation was previously performed in a small-scale dataset. The authors aimed to validate BT using the 2005 Korean nationwide anthropometric survey data. Methods: From the population used for the survey, we sampled children aged 0-12 years. The weights estimated by BT were compared with measured weights of the children using Bland-Altman analysis with results recorded as percentage differences. We measured the accuracy of BT, defined as within a 10% error of the measured weight, and the concordance of the color-coded zones derived from the estimated and measured weights. The accuracy and concordance were further assessed according to the age groups and body mass index-for-age Z-score (< -2, underweight; > 2, overweight or obese). Results: A total of 108,128 children were enrolled. The mean age was 55.2 ± 37.5 months. The bias was –5.4% (P < 0.001), and the limits of agreement were –28.3% and 17.6%, respectively. The accuracy and concordance of BT were 64.4% and 67.2%, respectively. Differences of no more than 1 color-coded zone between estimated and measured weights accounted for 89.8% and 84.1% of the under- and overweight (or obese) children, respectively. Conclusion BT accurately estimates weight in approximately two-thirds of Korean children. In addition, adjustment of 1 color-coded zone may be considered in children with extreme weight.

Background: Inter-hospital transfers of severely injured patients are inevitable due to limited resources. We investigated the association between inter-hospital transfer and the prognosis of pediatric injury using the Korean multi-institutional injury registry. Methods: This retrospective observational study was conducted from January 2013 to December 2017; data for hospitalized subjects aged < 18 years were extracted from the Emergency Department-based Injury in Depth Surveillance database, in which 22 hospitals are participating as of 2022. The survival rates of the direct transfer group and the interhospital transfer group were compared, and risk factors affecting 30-day mortality and 72-hour mortality were analyzed. Results: The total number of study subjects was 18,518, and the transfer rate between hospitals was 14.5%. The overall mortality rate was 2.3% (n = 422), the 72-hour mortality was 1.7% (n = 315) and the 30-day mortality rate was 2.2% (n = 407). The Kaplan-Meier survival curve revealed a lower survival rate in the inter-hospital transfer group than in the direct visit group (log-rank, P < 0.001). Cox proportional hazards regression analysis showed that interhospital transfer group had a higher 30-day mortality rate and 72-hour mortality (hazard ratio [HR], 1.681; 95% confidence interval [CI], 1.232–2.294 and HR, 1.951; 95% CI, 1.299–2.930) than direct visit group when adjusting for age, sex, injury severity, and head injury. Conclusion Among the pediatric injured patients requiring hospitalization, inter-hospital transfer in the emergency department was associated with the 30-day mortality rate and 72-hour mortality rate in Korea.

BACKGROUND: A kids café is a popular indoor playground in Korea that combines a playground for young children and a café for their caregivers. There have been no national reports about kids café-related injuries in Korea. This study investigated kids café-related injuries in Korea registered in a multicenter injury surveillance database and analyzed the risk factors for significant kids café-related injuries.METHODS: A multicenter cross-sectional study was performed using the Emergency Department-based Injury In-depth Surveillance registry in Korea between 2011 and 2016. Significant injury was defined as an injury requiring hospitalization or surgery. A multivariable logistic regression model was used to obtain the adjusted odds ratios (aORs) for factors associated with significant kids café-related injuries.RESULTS: Among 1,537,617 injured patients, we extracted 891 patients who were injured in kids cafés. Of these, 46 (5.2%) were admitted, and 39 (4.4%) underwent surgery. The most common injured anatomical site, injury type, and mechanism were lower extremity (28.2%), superficial injury (27.2%), and slip (27.1%), respectively. Among injury-inducing factors, significant injuries were most commonly caused by a trampoline (28.1%), and rock climbing equipment was the only risk factor in a kids café that led to significant injury after adjusting for age, sex, injury mechanism, and injured anatomical sites (aOR, 14.94; 95% confidence interval, 1.51–147.72).CONCLUSION: The rock climbing equipment in a kids café can cause serious injury to children. Establishing safety regulations for rock climbing equipment in kids cafés may have the greatest impact in reducing significant injuries requiring hospitalization or surgery.
Caregivers ; Child ; Cross-Sectional Studies ; Emergencies ; Hospitalization ; Humans ; Korea ; Logistic Models ; Lower Extremity ; Odds Ratio ; Play and Playthings ; Risk Factors ; Social Control, Formal ; Wounds and Injuries

Background: Understanding the changes in emergency department (ED) visit patterns during the coronavirus disease 2019 (COVID-19) outbreak is important for effectively operating EDs during the pandemic. We aimed to analyze the changes in pediatric ED visits during the COVID-19 pandemic and examine the relationship between the number of ED visits and the stringency of government social distancing measures. Methods: This multicenter retrospective study used data of pediatric (age < 18 years) ED visits in Seoul metropolitan area from June 1, 2018, to May 31, 2020. Patient demographics, ED results, and diagnoses were compared during the COVID-19 period and the previous year.To evaluate the effect of the stringency of social distancing measures on the number of ED visits, a Poisson regression model was developed with month, year, and the average monthly Government Response Stringency Index (GRSI) as fixed effects. Results: In total, 190,732 patients were included. The number of pediatric ED visits during the COVID-19 period was 58.1% lower than in the previous year. There were disproportionate decreases in the numbers of ED visits for children in early childhood (66.5%), low-acuity children (55.2-63.8%), those who did not use an ambulance (59.0%), and those visiting the ED for noninjury complaints (64.9%). The proportion of admissions increased from 11.9% to 16.6%. For every 10-point increase in the GRSI, there was a 15.1% decrease in monthly ED visits. Conclusion A striking decrease in pediatric ED visits was observed during the COVID-19 outbreak, the scale which was associated with the stringency of government policies.Changes in the number and characteristics of children visiting the ED should be considered to facilitate the effective operation of EDs during the pandemic.

Background: Understanding the changes in emergency department (ED) visit patterns during the coronavirus disease 2019 (COVID-19) outbreak is important for effectively operating EDs during the pandemic. We aimed to analyze the changes in pediatric ED visits during the COVID-19 pandemic and examine the relationship between the number of ED visits and the stringency of government social distancing measures. Methods: This multicenter retrospective study used data of pediatric (age < 18 years) ED visits in Seoul metropolitan area from June 1, 2018, to May 31, 2020. Patient demographics, ED results, and diagnoses were compared during the COVID-19 period and the previous year.To evaluate the effect of the stringency of social distancing measures on the number of ED visits, a Poisson regression model was developed with month, year, and the average monthly Government Response Stringency Index (GRSI) as fixed effects. Results: In total, 190,732 patients were included. The number of pediatric ED visits during the COVID-19 period was 58.1% lower than in the previous year. There were disproportionate decreases in the numbers of ED visits for children in early childhood (66.5%), low-acuity children (55.2-63.8%), those who did not use an ambulance (59.0%), and those visiting the ED for noninjury complaints (64.9%). The proportion of admissions increased from 11.9% to 16.6%. For every 10-point increase in the GRSI, there was a 15.1% decrease in monthly ED visits. Conclusion A striking decrease in pediatric ED visits was observed during the COVID-19 outbreak, the scale which was associated with the stringency of government policies.Changes in the number and characteristics of children visiting the ED should be considered to facilitate the effective operation of EDs during the pandemic.